The Downside of Sharing: Winter Bugs

Unfortunately, increasing numbers of us are experiencing this year’s particularly brutal seasonal flu (most frequently influenza A, subtype H3N2). The CDC’s latest FluView report and US map show that nearly all states have widespread outbreaks, and these reports don’t include the other winter illnesses that typically plague us, like the common cold, bronchitis, and pneumonia.

As we arm ourselves with flu shots, alcohol hand rub, tissues, and disinfecting wipes, these stats also remind us to please cover our mouths when coughing and sneezing, and to stay home if we feel even the mildest of sniffles coming on. Peak flu season is usually in January or February, and in the wake of this epidemic, we’d like to draw attention to our rapid-peer-review journal, PLOS Currents Influenza, which has an ongoing call for submissions in research related to the 2012-2013 seasonal influenza outbreak.

Now that you’ve triple-wiped down your keyboard, mouse, and phone, let’s have a look at some winter-illness-related research articles published in PLOS ONE within the past year.

Have you ever wondered why flu outbreaks always seem to occur during the winter months in the first place? A paper titled “Relationship between Humidity and Influenza A Viability in Droplets and Implications for Influenza’s Seasonality” may shed some light on the matter: listen to a featured podcast about this article in Scientific American, posted just last month. In this study, researchers investigated the relationship between humidity, a characteristic that can vary with temperature, and the viability and transmissibility of influenza A virus droplets. Researchers suspended the virus in different media and found that it didn’t survive as well when conditions were salty, or when the humidity was between 50 and 98%. However, the virus was extremely viable in mucus, and at conditions below 50% (dry) or above 98% (almost tropical), the virus was also quite viable and happy. The results of this research may explain why influenza outbreaks are prolific in both dry, cold weather as well as tropical environments.

For those of you that haven’t yet been convinced to run out and get a flu shot (cough, shown to be 60% effective, cough), you may be interested in a paper published last summer, showing that at least certain types of flu, like H1N1, may be transmitted before any clinical symptoms are noticeable. The study, “Transmission of a 2009 H1N1 Pandemic Influenza Virus Occurs before Fever Is Detected, in the Ferret Model,” finds that sick ferrets placed close to healthy ones could spread the flu by contact or droplet exposure a whole day before any clinical symptoms appeared. Interestingly, coughing and sneezing had less to do with transmission than did the viral concentration in the ferrets’ noses. Additionally, after day five or six of illness, viral transmission significantly decreased, supporting the idea that it may be safe to return to school or work after the worst of the illness has passed.

A recently published paper describes an investigation into the motivations behind Americans’ tendency to not get flu shots, a behavior that has been troubling and puzzling to both doctors and scientists alike. In “Behavioral Responses to Epidemics in an Online Experiment: Using Virtual Diseases to Study Human Behavior,” researchers created an “infectious disease outbreak” game in a virtual multiplayer online world to study how willing people were to protect themselves during epidemics. Players accumulated points depending on their health status and actions they took, but they needed to spend points to protect themselves and thereby reduce their chances of falling ill. Results indicated that a person was more willing to take self-protective action when the outbreak was severe, or when a prior experience with inaction had resulted in illness. Players were also more likely to take preventative measures if they were less costly, which indicated to researchers that decreasing the cost of the flu shot could ultimately decrease the overall prevalence of the disease.

These articles are just a tiny droplet in the bucket of influenza-related research published in PLOS ONE. Click here to read more research articles on one of the more common types of seasonal flu, the influenza A virus.

And, please stay safe and healthy in these remaining winter months!

Image credit:  the H3N2 virus, ID#13470, CDC


Yang W, Elankumaran S, Marr LC (2012) Relationship between Humidity and Influenza A Viability in Droplets and Implications for Influenza’s Seasonality. PLoS ONE 7(10): e46789. doi:10.1371/journal.pone.0046789

Roberts KL, Shelton H, Stilwell P, Barclay WS (2012) Transmission of a 2009 H1N1 Pandemic Influenza Virus Occurs before Fever Is Detected, in the Ferret Model. PLoS ONE 7(8): e43303. doi:10.1371/journal.pone.0043303

Chen F, Griffith A, Cottrell A, Wong Y-L (2013) Behavioral Responses to Epidemics in an Online Experiment: Using Virtual Diseases to Study Human Behavior. PLoS ONE 8(1): e52814. doi:10.1371/journal.pone.0052814

A selection of influential PLOS ONE papers on tropical medicine and malaria

For the XVIII International Congress for Tropical Medicine and Malaria Conference in Rio de Janeiro, PLOS ONE is highlighting eight recent articles.  Since January 2011, PLOS ONE has published almost 700 articles in the areas of tropical neglected diseases, tropical medicine, and malaria.  We’re sharing with you some of the papers that have received the most attention.  The authors on these papers come from across the globe, representing Brazil, Colombia, Ethiopia, France, the Netherlands, Papua New Guinea, Spain, Sri Lanka, Switzerland, the United Kingdom, and the United States.

One paper in particular has stood out.  Researchers found a novel therapy that could revolutionize the treatment of viral infections from the common cold to Ebola.  The therapy eliminates cells that contain viral RNA while leaving uninfected cells unharmed.  In the study, the therapy was effective against 15 different viruses, including dengue flavivirus, rhinoviruses, and H1N1 influenza virus.

An article published last month reported that malaria incidence in Sri Lanka has declined by 99.9% since 1999, despite ongoing conflict in the country.  The success of the malaria program could be explained in part by effective prevention measures, early detection, and maintaining the program in conflict zones.  In less than a month, the paper has received over 1,000 views.

Bacteria on people’s skin can affect how attractive they seem to malaria-transmitting mosquitoes.  Research published last December found that malaria mosquitoes preferred people whose skin had an increased number of bacteria but fewer overall types.  The article received significant press coverage and has been viewed almost 10,000 times.

Although a vaccine that blocks malaria transmission is theoretically possible, several obstacles have prevented its development, including producing Plasmodium parasite antigens in a cost-effective manner.  A paper published in May 2012 showed algae can make Plasmodium proteins that can elicit an antibody response.  This approach could bring down overall costs of a vaccine.  Since publication this paper has been viewed over 3,500 times.

A different approach to combatting malaria is to increase the mosquito’s defenses against the parasite.  A paper published in January 2011 showed that it is possible to insert an anti-malarial gene into a specific location in the Anopheles gambiae genome.  This technique decreased infections of Plasmodium yoelii nigeriensis and could be effective against other Plasmodium parasites.  Since publication this paper has received over 2,000 views.

The results from a World Health Organization-led effort to estimate the global incidence of leishmaniasis, a parasitic disease spread by sandflies, published in May 2012.  To obtain an accurate estimate of the disease burden, the authors collected data from 98 countries and 3 territories.  The authors stressed the importance of this in-depth assessment in helping policy makers and aid organizations determine funding priorities for this underreported disease.  The paper has been viewed over 5,000 times.

One strategy parasites use to evade the host’s immune system, initiate infection, and even manipulate host behavior is to imitate the host’s proteins.  A study published in March 2011 presented a method for scanning entire parasite genomes to identify proteins that are mimicking host proteins.  The paper received over 4,000 views and was featured on the This Week in Parasitism podcast.

Finally, a new method for diagnosing infection by Schistosoma mansoni, the parasite that causes schistosomiasis, was published in June 2012.  This method, which is based on detecting the parasite’s DNA, provides greater sensitivity than the most routinely used diagnostic approach, requires only a urine sample, and has a relatively low cost.

If you are at the ICTMM, we hope that you have had a chance to stop by the PLOS booth, pick up one of the PLOS ONE postcards, and meet staff from PLOS Pathogens and PLOS Neglected Tropical Diseases.

Acknowledgment:  Thank you to Martin Fenner for helping us use the PLOS Article Level Metrics to identify influential PLOS ONE papers in the areas of tropical neglected diseases, tropical medicine, and malaria.